Electric switch



Patented July 21 1885.

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UNITE STATES PATENT OFFICE.

EDMUND B. NIOOLAUS, OF CLEVELAND OHIO.

ELECTRIC SWITCH.

SPECIFICATION forming part of Letters Patent No. 322,745, dated July 21,1885.

Application filed January 6. 1885. (N0 model.)

a citizen'of the United States of America, re-

siding at Cleveland, Ouyahoga county, Ohio, have invented certain new and useful improvements in Electric Switches, of which the following is a specification.

My invention relates to switches adapted for use on circuits where currents of great strength are employed, such as an incandescent-light circuit.

It consists of a hand-lever of conducting material pivoted to a plate forming one terminal of the circuit and adapted to be turned to make contact with a plate forming the other terminal, thereby completing the circuit through itself. When the lever is so turned, itis held in the closed position by its frictional pressure against the terminal plate, while a spring connected to the lever has a constant tendency to draw it away from the contact point and break the circuit. This spring,however, is of such a strength that when there is a good frictional contact between the lever and the terminal plate, it will not have sufficient power to withdraw the lever; but when the lever is moved slightly by hand it becomes released to the power of the spring and flies back, instantly breaking any are that may be formed between it and the plate. Whenever,

also, the friction becomes less by the wearing away of the parts, or whenever,in closing the circuit, the lever is not moved far enough to insure good electrical connection, the spring will act to break the circuit and give indication of the fault.

My invention is illustrated in the accompanying drawing.

A is a circular base having a flange, M, which serves to hold an inclosing-cap, (not shown,) and within which are the parts of the switch.

E is the switch-lever, its outer end projecting through a break in the flange lVLand provided with an operating-handle, L, while its inner end is pivoted to the under side of plate D, so as to afford it aswing in a sector-like depression in the base from the position shown in full to the position shown in dotted lines. In the latter position it crowds under the projecting lip on plate B, so as to make a good electrical connection therewith, and be held against the withdrawing tendency of spring S by means of the friction. One terminal of the circuit is brought to bindingpost K on plate D, and the other terminal to post G on plate 0, from whence it passes by fusible strip '1? toplate B, so that lever E, when in contact with B, closes the circuit.

When in its closed position,the switch may be opened by a slight upward movement of the handle L, sufficient only to overcome the friction. the rest of the movement being made under the action of spring S.

If the parts have become worn, or if the lever is not drawn fully'over in closing the circuit, it will be drawn back by the spring, giving indication that the friction should be increased by resetting the parts, or that the switch shouldbe moved over to its full limit.

I am .aware that it is old to use afusible wire or conductor in an electric circuit, and hence I make no broad claim thereto. I am also aware that it is old to combine a spring with the lever of an electric switch in such a manner that the spring will exert its power in retaining switch-lever in both its open and closed positions. This construction of switch is defective because, should the switch-lever make a poor contact with the contact spring or plate, owing to the wearing of the parts, bending of the contact spring or plate, the lodgment of foreign matter between .the engaging surfaces, or the failure of the operator to force the switch-lever in firm engagement with the contact plate, it would result in a poor electrical contact not noticeable perhaps, but which would cause deleterious heating of the parts and waste of current strength. In my improved switch the spring is connected with the switch-lever in such a manner that it tends at all times to disrupt the contact by throwing the switch-lever into its open position; and hence it is impossible for an attendant to leave it closed unless it has been forced into such snug engagement with its contact that its frictional engagement therewith is sufficiently strong to overcome the opposing power of the spring, and when this is done it insures a good and reliable electrical contact.-

WVhat I claim is- 1. In an electric switch, the combination,

with the two terminals, of a switch-lever pivoted to one terminal and constructed and arranged to make a sliding frictional contact with the other terminal, and a retractile spring secured at one end to the switch-lever and at its opposite end to a fixed support,and arranged to have a tendency at all times to disrupt the contact and throw the switch-lever to its open position, substantially as set forth.

2. In an electric switch, the combination, with the two terminals and a fusible strip interposed in the circuit, of aswitch-lever pivoted to one terminal and constructed and arranged to make a sliding frictional contact EDMUND B. NIOOLAUS.

Witnesses.

E. G. SEWARD, S. G. NOTTINGHAM. 

